Sunday, March 01, 2015

The Popular Abstract of My PhD Dissertation

In less than one month's time, I am going to have my doctoral defense in Helsinki, Finland. In order to register my thesis in the university E-thesis System, I need provide two different versions of abstract. One is called scientific abstract which is mainly for the experts working in the related fields, the other is called popular abstract which targets the public who does not have prior knowledge of the subject and it must be in Finnish or Swedish. I am not sure whether this is a unique invention in Finland, but asking a non-Finnish speaker to provide such an abstract without providing enough help in the University seems a bit ridiculous.

Anyway, thanks to Maria's great help, I got the popular abstract done, though I really doubted at some point whether she really knew what she was doing there. :D Interestingly, having no field knowledge at all turned out to be a great advantage when Maria was trying to write the popular abstract for me. Here you can find two abstracts as following.

The Scientific Abstract

In-network caching aims at improving content delivery and alleviating pressures on network bandwidth by leveraging universally networked caches. This thesis studies the design of cooperative in-network caching strategy from three perspectives: content, topology and cooperation, specifically focuses on the mechanisms of content delivery and cooperation policy and their impacts on the performance of cache networks.

The main contributions of this thesis are twofold. From measurement perspective, we show that the conventional metric hit rate is not sufficient in evaluating a caching strategy on non-trivial topologies, therefore we introduce footprint reduction and coupling factor, which contain richer information. We show cooperation policy is the key in balancing various tradeoffs in caching strategy design, and further investigate the performance impact from content per se via different chunking schemes.

From design perspective, we first show different caching heuristics and smart routing schemes can significantly improve the caching performance and facilitate content delivery. We then incorporate well-defined fairness metric into design and derive the unique optimal caching solution on the Pareto boundary with bargaining game framework. In addition, our study on the functional relationship between cooperation overhead and neighborhood size indicates collaboration should be constrained in a small neighborhood due to its cost growing exponentially on general network topologies.